Rectifier and method of making the same



Jan. 27, 1948. MJF, sKlNKER 'ET AL 2,434,967

RECTIFIER AND METHOD OF MAKING THE SAME Filed 'Oct 26, 1943 3 Sheets-Sheet 1 ATTo/e/VEY Jan. 27. 1948.

M. F. sKlNKr-:R |:r Al.

RECTIFIER AND METHOD OF MAKING THE SAME Filed Oct. 26, 1943 3 Sheets-Sheet `2 TYURN Jam 27. 1948. M. F. sKlNKl-:R ET Al. 2,434,967

RECTIFIER AND METHOD OF MAKING THE SAME Filed Oct. 26, 1945 5 Sheets-Sheet 3 A TTRNE' Y Patented. 27,

UNITED o STATE-'s APA'ria-ixi'r o Price 4 2.434.967 o f RECTIFIER AND METHOD 0F K THE SAME e w o Murray F. Skinker, Montclair, N. J., Ivanhoe P. Denyssen. Lansdowne, Pa., and Max G. Kolmes, Brooklyn, N. Y.. assignors to Federal Telephone and' 'Radio Corporation, New York, N'. lisa corporation of Delaware l Application october zo, 1943, seriaine. 507.611` l This invention relates to improvements in rectiers and methods of making the saine,i and more particularly to small selenium rectiflers and a preferred method of making the same on a Fig. 131s an end view of the same clamp:

iscieime.' (01.115.466) l Fig. 14 is` a top plan view cfa completely asl,

sembled rectler unit;

Fig. 15 is'a longitudinal cross-sectional View on a greatly enlarged scale taken along the line quantity basisw 5 I5--i5 of Fig. 14;

An object of this invention is to provide a novel Fig. 16 is a transverse cross-sectional view selenium rectifier of sturdy and simplied conltaken along the line Iii- I6 of Fig. 15. struction. It is believed that the construction of the indi- Another object of this invention is to construct vidual rectifier units according to our invention, a small selenium rectifier from a minimum o `iii aS Well as the actual methOd 0f prOduCing these correlated preformed parts. units, can best be described by following through Afurther object of this invention is to produce a preferred method 0f producing the same in `a small compact selenium rectifier unit all of large quantities. As will be seen in Figs. 1 and '2, whose parts and whose methods of assembly lend we may start with a substantially rectangular themselves to the cheap production of suchrectil5 metal base strip which may be first degreased, fiers inlarge quantitiesetched and nickel plated in a known manner stili another object of this invention is directed and then vcovered withv a Selenium coating l2. to a novel method of making small selenium reo- This selenium coating may be applied in any welltifiers in mass production. known manner as by setting the base strip Ill Other objects will appear from the following 20 up in a :lig (not shown). sprinkling the plate with description of an 'illustrated embodiment of the selenium powder with or'wlthout a mask. presslnvention taken together with the attached drawing the selenium and then Dassin?. the Strip ings wherein: through a heat-treating overland fuming. These Fig. 1 ls e top plan view of a selenlumc0ated steps are well-known tothe art and are not, in base electrode strip; l 25 themselves. to be consideredias part of the Dres- Flg 2 ls an end view of the base Strip shown ent invention. Preferably, the metal base strip in Fig. 1; f' lll is formed with a pair of short depending legs x Fig 3 is a fop plan View of an insulating I4 for setting the same up in the jig and also gummed paper strip; o "30 with a pair of locating Aholes i6 and i8.

Fig. 4 is a plan View of the base electrode After the Selenum has been as in the strip of Fil; 1 with the gummed pape). strip manner 4described above. van insuating strip, plied and blanked out to form a plurality of indi- Preferably in the form 0f gummed aver 2,0- W0' y vidual rectifier' bases vided with a plurality of `longitudinally spaced Fig. 5 is a longitudinal cross-sectional view nf Smau holes 22 and with locatifvz holes 24 and' 2 6 the blanked-ut strip of Fig. 4 placed in a fixture' 35 similar to those in Ithe base-electrode strip illus with the additin of a spray mask', and showing placed over the latter and cemented thereto. the counter-electrode alloy sprayed there- While the insulating Strip 20 moy Pe made .to i thil'cgranlg'prtml section of one of 4o formed with a rubber adhesive which softens Fig. 'I is a top plan view showing the individual Eftrrfatmg' This Wm rmly bond the inguat' p to the base-electrode strip. and more rectifier units with the counter-electrode alloy particularly over the selenium coating on the applied and the spray mask removed, and one p latter. e de of the mettilbase filmed 0m 45 After the irl ienne strip 20 hee been applied Fig' 8' is a top pian View of aplurality of indi to the base-elec rode strip lil. the latter is placed vidual insulating bases for the rectifying units; m a suitable punch press or other machine whim Fig. 9 is ,e Side View 0f en enlarged Scale 0f will blank eut'the bese eine inte theshepe inueone of the .insuatmg bases illustrated in F13 3? trated in g". 4. lThe blankine operation results Fig. 10 is a transverse cross-sectional view 50 ln a .plurality longitudinally spaced substantaken along the ne 'o 'o f Fig' 9; tlally rectangular units 28 which later form bases Fig. 11 is a top plan view of a metal clamp t0 for-individuel rectinei-s.l These individuel umts be'used With each recliner unil?? are interconi'iected` with the sides of the origi- Fig. 12 is a side view of the same clamp: 55 nal base-electrode strip by relatively narrow 'bridges 30 and 32. At this time, also, the ends 3 of the bridges 30 may be slightly notched, as in dioated at 84 to assist in breaking the units away from the side strips, and additional notches 86 may be formed to assist in removing the whole side oi' the metal base strip from the remaining portion thereof. Likewise, notches 38 may be formed at the junction between the leads/j or bridges 32 and the other side of the metal base strip, for the same purpose. It will be noted that when the individual rectifier units are blanked out in the manmner described above, the small holes 22 in the insulating paper strip 20 are so spaced as to fall substantially in the center of each one ofthe units 28. y

The blanked-out base is then placed in a iig or iixture 40, shown in Fig. 5. This ilxture is provided with a pair of locating pins or extensions. 42 and `44 which pass through the locating holes in the base strip to hold the same in proper position on the ilxture. A mask 46 is then placed over the assembled base strip. This mask is provided with a plurality of spaced openings 48, each of these openings being coaxial with and slightly larger than the holes 22 centrally positioned on the individual units 28. Counter-electrode alloy material is then sprayed or otherwise applied through each of the holes 48 to form a small counter-electrode alloy mask 60 on each rectifier unit. As is more clearly shown in enlarged Fig. 6 the counter-electrode alloy 50 penetrates through the holes 22 in the paper mask to'contact the selenium layer i2 on the metal base Ill. If this counterelectrode alloy is thinly applied it will have a cup-shaped central portion i just above each hole 22, with va relatively thin circular ilange 53 on the paper strip about each of the small holes.

The'mask 46 is then removed and, for the purpose of placing the rectifier units in their insulated bases, one side of the metal base, strip rray be broken oil along the notches 84 and 36 so that the strip at this time will have the appearance as shown in they-top plan view of Fig. 7.

The individual insulating bases: for the rectifier units may also be made by mass production methods. A sufficient number cf insulating bases for all oi' the rectiiler units. formed from one metal base strip. may be moulded together in one piece from any suitable mouldable insulating material. Moulding methods may follow known forms which need not be described here and which form no part of our particular invention. However, after the insulating bases have been moulded the composite moulded piece is preferably separated into two parts 52, 52' as shown in Fig. 8, with certain of the insulating bases 54 remaining attached to the side strip 52, as by bridges 56, while the remaining insulating bases, remain attached to the side strip 52 as by the bridges 56'. The individual insulating bases'54 are spaced in the mould with the same longitudinal spacing as is provided for the stamped-out individual rectier bases 28, but when the moulded structure is separated as indicated in Fig. 8, alternate insulating bases are attached to the indiel'aliy therefrom a short distance. The posts at same length but oi.' somewhat less width than the' central section 60 of each of the insulating bases, 10 while the integral extensions 30 and 32 of the individual rectiiier units have a width which is no greater than the grooves 64 between the end posts 62 of the insulating bases 54. Thus, the individual rectifier units 28 may be placed into l5 their individual bases which are still attached to the moulding base strip. For example, one oi.' the strips, such as 52, may be placed in juxtaposition with the blanked-out plurality of rectifier units of Fig. 'I in which case, for example, the rst, third, fifth, etc.; rectifier units may be forced into its corresponding insulating base, broken oil from the metal base strip l0 along the notches '38, and the strip 62 with its individual insulating bases 54 and the enclosed rectifier units 28,

u removed and set to one side. The insulating strip 52' with its attached insulating bases is then placed in juxtaposition with the even rectifier units, the latter pressed into place and broken oft 4and the remainingportion of the` base-electrode an Strip discarded.

' In order to iirmly secure each rectifier unit to its individual insulating base we prefer to use a clamping device in the form of an inverted U, and illustrated by way of example in Figs. 11, 12 and 13. It will be seen that each one of these clamps '88 is formed with a raised blister 10 on its upper side and with a pair oi' opposite depending clamping arms or sides 12. Longitndinally from one side of the top there also extends a tongue or a strip 68, preferably formed integrally with the rest of the clamp. One of the insulating strips, such as 52`with its attached insulating bases 64, and thev pressed-in rectiiler units 28 are then taken and the clamps 66 pressed ldown so that th top of the clamp 66 is in contact with the counter-electrode alloy on the top of each rectiiying unit, while the lower ends of the sides 'I2 of each clamp may be bent about the bottom of each insulating base.- The purpose of separating the moulded base into two widely spaced units is to permit the proper insertion and clamping of the clamp 66. If the mould were not separated in the manner described above the individual rectier units would be too closely spaced to permit easy attachment of the individual clamps. The close spacing of the individual insulating bases and of the individual rectifier units permits, of course, a maximum utilization of material during the blanking-out and moulding operations. When the clamps are attached to rectifier units attached to one strip 52,

other clamps may be then attached to the rec- `tiiler units attached to the strip 52'. After the clamps are attached the completed units may be broken off from the moulded side strips. and for e5 this purpose, during the moulding operation notched or weakened sections 58 (Fig. 8) will have been formed between each insulating base 54 and the bridging strip 56.

Each completed rectiiier unit will have the 70 appearance shown in Fig. 14, and illustrated further on a much larger scale as shown in Figs.

l5 and 16. It will be noted that each metal clamp 66 has a length which is substantially equal to the distance between the pairs of posts 62 on opposite ends of the insulating base 60, while the a direction opposite to the extension 30. Since the clamp 68 contacts the counter-electrode alloy 50 on the top of the rectifier unit, while the extension 30 is an extension of the metal base I0 of each rectifier unit, the extensions'ii and 68 may thus form a pair of lead terminals for each rectifier unit.

As previously pointed out, '.each of the metal clamps 86 is preferably formed with a raised hollow blister 10. This blister is so positioned that it will be'positloned substantially directly above the depressed portion i of the counterelectrode alloy, or in other words, that part of the counter-electrode alloy which is in contact with the selenium. However, the metal clamps 66 still contact the flange section 53 of the counter-electrode alloy. This construction permits a tight clamping action of the clamps 66 about the assembled insulating base and rectifier unit, while still preventing undesired direct pressure upon the small rectifying contact area between the counter-electrode alloy and the selenium. After completion of the assembly of the rectifier units as above described, lead wires may be attached to the lead terminals 30 and 68 and, if desired, additional insulation may be applied to the rectifier unit as a whole, as by covering the same with insulating tape or dipping the whole unit in some moisture-proof lacquer or paint. Ii a mask was not used when originally applying the selenium to the metal base plate. the selenium on the extension 30 will be removed in any simple manner before attaching wire leads thereto.

While we have described above a preferred form of rectifier unit and a preferred method of making the same, lt will be obvious to those skilled in this art 'that variations in detail in both the construction of the rectier and the method may be used. Additionally, the device and the method of making the same can be used in connection with rectifying materials other than selenium. It is particularly pointed out that the method of constructing and assemblingthe rectier units has been described in a logical sequential order, but that obviously some changes in the sequence of the procedure couldv be made without changing the basic conception of the method. Insulating material other than gummed paper would be suitable for use in the present invention, and in this case the insulating material could be preformed into shape instead of first attaching it to the metal base strip and blanking out the combination. Instead of applying selenium over the entire metal base strip in the first instance, if desired, a suitable mask could be used and only that portion of the base strip to be blanked out for the individual rectifier units could be covered.

Accordingly, while we have described above the principles of our invention in connection with a specific device and a preferred method of making'the same, it is to be clearly understood that this description is made only by way ofrexample and not as a limitation on the scope of our invention as set forth in the objects and the accompanying claims.

We claim:

1. A rectifier comprising, in combination, an insulating base, a metal plate having a narrow extension, mounted on the upper surface of said base, a coating of rectifying material on the upper surface of said metal plate, a layer of insulating material having an opening therethrough covering said rectifying coating, counter-electrode alloy on said insulating layer and extending through said opening to the rectifying layer, and a metal clamp in the general form of an inverted U about said insulating base, metal plate, rectifying coating, insulating layer and counter-elec-f trode alloy, said clamp having the inner side of its top contacting said counter-electrode alloy and its arms gripping the underside of said insulating base. whereby said metal clamp forms one terminal of the rectier and the extension of said metal plate the other rectifier terminal.

2. The combination according'to claim l, in which said rectifying material is selenium.

3. The combination according to claim 1, in4 which said clamp is provided with a narrow in.

tegral projection extending in a direction opposite to the narrow extension of said base plate, and forming said one terminal.

4. Thecombination according to claim 1, in which the top of said clamp is formed with a small. hollow, raised blister directly above the opening through the insulating layer :to relieve the contact between the counter-electrode alloy and the rectifying layer at that point of clamping pressure.

5. The combination according to claim l, in which said insulating material is gumrned paper.

6. Rectifier comprising, in combination, an insulating base having a substantially plane rectangular central upper surface, with four raised posts at each corner projecting laterally of the insulating base, the posts at opposite ends of the face being separated by ya relatively narrow groove, a generally rectangular metal plate on the upper surface of said base, said plate being provided with an integral narrow extension on one end projecting through one groove beyond the insulating base, and a short integral tongue on its other end projecting into its opposite groove. a coating of rectifying material on the upper surface of said metal plate, a layer of insulating material having an opening therethrough covering said rectifying material, counter-electrode alloy on said insulating layer and extending through said opening to the rectifying layer, and a metal clamp about said insulating base, metal plate, rectifying layer, insulating layer, and counterelectrode alloy, in the general form of an inverted U having the innerlside of its top lying within the insulating posts on top of and contacting the counter-electrode alloy, and its armsv extending downwardly along the sides of said and the'rectifying layerlat that point of clamping' pressure.

9. The combination according to claim 6, in

which said insulatingmaterial is gummed paper.

10. The combination according to claim 6, in which said clamp is provided with an integral projection on its top extending througlisaid opposite grooves outwardly of the base and forming said one terminal.

11. The combination according to claim 6, in`

plate, blanking out the metal plate and the at-v tached paper into opposite,longitudinallyeX- tending metal borders connected by a plurality of paper-covered transversely extending, similarly longitudinally s'paeedbridges, each bridge comprising two relatively narrow sections, one connected to each border, integrally joined. by a .wider substantially rectangular section with the holes in said attached paper positioned substantially in thecenter of each rectangular section, covering the blanked-out strip with a mask having openings therethrough concentric with and slightly larger than the holes in the paper, applying counter-electrode alloy through the openings of said mask onto the paper and through its holes to the selenium layers on the respective rectangular sections, placing each of the rectangular sections on one side of individual pre-formed insulating bases, and pressing a metal clamp about each assembled section and base with one portion of the clamp contacting the counter-electrode alloy and another portion gripping the underside of the base, and then breaking each bridge from the metal borders.

13. A metal contact rectifier comprising an insulating base, a rectiiier element mounted on the base comprising a base electrode, a semi-conducting layer, a counter-electrode and insulation located between the outer portion of the semiconducting layer and the counter-electrode, and a sheet metal contact member bearing against said outer portion of the counter-electrode, the

insulating bases mounted in aiignment'on a common support, assembling a rectifier with each base and thereafterseparating the base from the support.

16. A method of manufacturing metal contact rectiiiers which comprises' forming a plurality of rectifers mounted in alignment'on a common support, forming a plurality of insulating bases mounted in alignment on a common support. assembling the rectifiers and bases and thereafter separating the'` bases and rectifiers from said supports.

17. A metal contact rectiiler comprising an insulating base having a recess, a rectier element fitted in the f recess and comprising metal electrodes engaging opposite sides of a semi-conducting layer, and a metal clamp formed with a raised hollowblister and arranged with its sides extending angularly therefrom and about said insulating base and rectifier. said clamp having its inner side around said blister contacting one of said metal electrodes and its sides gripping the underside of said insulating base.

18. The combination according to claim 1'1. in which the other metal electrode is provided with an integral yextension forming one rectifier terminal and saidfmetal clamp is provided with an integral extension forming a second rectiiier terminal. x y

19. A metal contact rectiiier comprising an inu sulating base, a rectifier element mounted on the base comprising a base electrode, a semi-conducting layer, a counter-electrode, and insulation located between the outer portion of the semi-conducting layer and Ithe counter-elec` trode, and a metal clamp formedwith a raised hollow blister, said blister shaped to permit said metan clamp to make contact only with the iiange of lsaid counter-electrode, 4said clamp having sidesv extending angularly therefrom and about said insulating base and rectifier element, said clamp having the inner side of its top contacting said counter-electrodeand its sides gripping the underside of said insulating base.

MURRAY F. SKINKER, IVANHOE P. DENYSSEN. MAX G..KOLMES.

`mnrERENcEs CITED The following references are of record in the iile of this patent:

rectiers which comprises forming a plurality of UNITED STATES. PATENTS Number 

